Variable-speed transmission



' Juiy16,1946. .1. o. HAMREN- Y v 2,404,229

VARIABLE SPEED TRANSMISSION- Filed Jan. 50, 1941 s Sheets-Sheet 1' July 16, 1946. J. o. HAMREN 2,404,229

VARIABLE SPEED TRANSMISSION Filed Jan. 50, 1941 5 Sheets-Sheet 2 INVENTOR.

dasz /l 0 Ham/aw July 16, 1946. J, O HAMREN 7 2,404,229

VARIABLE-SPEED TRANSMISSION Filed Jan. 30, 1941 5 Sheets-Sheet 3 u Q If INVENTOR;

JOSEPH O.HAMI2EN ATTORNEY.

' July 16, 1946. J. o. HAMRE N VARIABLE SPEED TRANSMISSION v Filed Jan. so', 1941 5 Sheets-Sheets Patented July '16, 1946 I 25404329 Y VARIABLE-SPEED TRANSMISSION Joseph 0. 'Hamren, Minneapolis Application January 30, 1941 Seriall"No.376;626

16 Claims.

This invention relatesto a powertransmitting means and particularly to a variabl speed transmitter of the fluid type adaptedfor use in driving an automotive vehicle. I

The particular-type of-fluid transmitterissimilar to'that'inapplicants Patent Number L966;

892, granted July 1'7. 19-34, for Turbine, to which patent reference will be made. The present invention embodies improvements upon'the 'device disclosed in said patent.

,It-isanobject-of thisinvention to provide a simple "and efficient variable speed fluid transmission device which may be easily installed in automotive vehicles. The power transmission de- "Vice-per se ls of course, capable of variedother uses.

fIt is-a furtherobject of the invention to provide a variable speed fluid transmissionnnit which is capable of transmitting power with gradual variations in speed. V

Another object of=the inventionis to provide a simple and efficient power transmitting unit which maybe easily installed in anautomotive vehicle and which is adapted to'b connected to and drive the rear wheels of said vehicle.

' It=is also an object of the invention to'provide a variable speed fluid transmission unit which maybe used in an automotivevehicle and form -a- -dual drive-kfor the wheels thereof a clutch not being used; 7 v I 'It isalso an object of the inventionto "provide a structure comprising a fluid transmission device having units arranged to bedrivenin op- .Posite directions and to be connected with the wheels of the automobile.

It is further an object of the inventionto providean automotive vehicle Witha-fluid transmission device comprising-a pair of shafts, a pair of rotors for each shaft, the-rotors of said pairs being arranged to be driven in Opposite directions to provide forward and rearward drives, said shafts being adapted to be connected to the wheels of the vehicle.

It is still another object of the invention to provide an automotive vehicle with a fluid'transmission device comprising a. pair'bfyshaftsarranged to be connected to'the Wheels of the vehiclega pair of rotors for each shaft and sleeves enclosing said rotors adapted to be relatively moved to-supply fluid to the "desired-rotors for 1 forwarder rearward driving.

'- It is a further object of th invention'to pro- -v ide 'an automotive vehicle with'a fluid transmission device comprising shafts adapted;to be -=connected to the Wheels cfsaid'vehicle,a 'pair 2 of rotors for each -shaft,the rotors of eachpair being arranged to be driven inoppositedirec tions -'f or producing forward and' rearward speeds together with means for connecting the desired rotors t said shafts.

These and other objects and advantages of. the invention-Willbe fullyset forth in the following description-madein connection with the accompany-ing drawings in which like referenc characters refer tosimilar parts throughout thetseveral views and in which: 4 Fig. -l is atop plan view diagrammatically showing the frame, wheelsand part of the body of an automobile with the invention applied thereto; g

i'FlgfZ is'a partial viewsimilar to Fig; 'l shown on an chlargeds'cale, some parts being broken Fig. 3 is a 1 fragmentary section taken on line '3'=3 ;of-F-ig. 2;

EFig. 4 is a vertical'section takensubstantially 'on line 4-4 ofFig; 5 as indicated by the-arrows;

someparts'being shown in side elevation; j-Fig.' 5is avertical section taken substantially on line 5- 5 of Fig. 4-as indicated by the arrows;

'=Fig. dis a vertical-section taken substantially on line '6'6 of Fig. 4'asindicated by the arrows; and

-Fig'.- 7 is a top plan. view of the transmission ulllt-ysOIlle parts-being broken away and others shown inhorizontalsection.

*Ref erring tothe drawings; particularly Fig. 1, r

theoutline of an automotive vehicle is shown wherein the' chassis in general is designated H. Said vehicle-is equipped with-the conventional engine I'Zsuch as one of" the internal combustion type. Connected to 'and driven by the engine in any suitablemanner isapump I3. While various types ofpumps might be used, preferably one capable ofpositively circulating a liquid through the system and of building up a pressure therein is-used. A discharge pipe "[4 and inletpipe 15 are connected to pump I3 and these pipes are connected'attheir Y other ends to my-variable fluid power transmitting unit mounted onthe rear axle of the'vehicle H and designated generally-I6. Various means for mounting unit Hi on the vehicleor aspart of therear axlestructure'may 'beusedas long as it be so mounted that unit l6 can be connected in any suitable manner to the rear wheels 33 and 34 of said vehicle.

;Means"is also provided for controlling the device to eiiect variable speeds in transmitting povyergto ,said'rearwheels. While this. means 7 couldtake -various forms, in the embodiment "of 3 the invention illustrated, thesame comprises a crossbar I! mounted on the unit [6, said crossbar in turn being connected at opposite ends to rods or cables 18 and I9 respectively which are connected to and controlled by foot pedals 20 and The mechanism operated by 2| respectively. the crossbar I! will be later described in connection'with the means for controlling the speeds of my device.

In Figs 4 to v the unit It is illustrated more in detail. The mechanism shown in said figures carried in ball bearingcages 55 disposed between said rotors and end plates 56 seated in recesses V in end members 2B'and 29 respectively; Memis a refinement of an improvement upon that shown in the patent above identified; Said-unit comprises a casing having end portions 28and'; 29 and a peripheral portion 21. End members 28 and 29 have disposed therein ball'bearings35 and a sealing member 31 is providedat the outer side of each of said bearings. Shafts30 "and 32 are journaled in bearings 35 respectively having splined portionsiprojectingto the outer side of thex'end members 28 and 29, which portions will be; connected in any desired way with the wheels came 34. End plates 39rvare secured to the ends of end members 28 and 29 by bolts 40, said shafts extending through said end plates. End member 28. has an annular chamber 28a therein which communicates with an outlet conduit 28b. forminglpart of end member 28, the samehavinga flange 280 at its end to which asimilar flange on conduit I5 is connectedjby suitable bolts (not shown); End member 28 has inlet openings 28d and 28a forthe transmission of fluid as will be later described. End member 29 has an annular chamber 29a and also hasinlet passages -2 5b;and a 29c therein. Passages 28aand 29a are connected zbyjal passage 44 extending longitudinally of the casing as shown in Figs. 4 and 5. Passage 414 is :formed in an enlargement atone side of member 21. Endmembers 28 and 29 are secured to memperil! by the headed screws '4! s Member 2'l;has a .:projection 2la;-at; one side thereof to which is connected a member 45;. JPortion 21a has a central part 211) and passages 2'lc and 21d extend throughportion 21a at .eachside of portion 21b:- into'-v the chamber 21e immediately within the 'rportion2'lz Member 45 constitutes a conduit, the

passage therethrough' being dividedbya central rib 45a. A sleeve is provided which is concentric with member 21 and which is provided with end flanges 41a bearing at their; ends against the end members 28 and 29 respectively. Said flanges have passages 41b therethrough which are adapted to register with the inlet openingsZBc and 286 respectively in members 28' and 29; Sleeve 41 is mounted for rotation on a second sleeve 48 about which it fits tightly, sleeve 48 being: held stationary by dowel pins 49 extending'through end members 28 and 29 respectively thereinto, Sleeve 4'! is also formed with a series of ports or openings 410 in the wall thereof and the sleeve 48 is formed with a series of openings lfib adapted to register with the series of openings 41c upon properrelative rotation of sleeves 4! and 48. A second series of ports or openings 41d are formed in the sleeve 41 and these are arranged to register with a second series of ports or openings 480 in the inner sleeve 48.

a Within the sleeve 48 and between end-members-28 and 29'are mountedfour rotors or rotating units-designated 50, 5|, 52 and '53. These units have-hubs containing ball bearing assembl-ies-54, '13, 13 and 51 respectivelyupon which said rotors are mounted for rotation about shafts 30-and 32. Rotors 50 and 55 are similar in construction and these bear against ball bearings bers 55 have oil grooves 55a therein. Rotors 5| and 52 are similar and these bear at theiradja- 77 cent sides on ball bearings carried in ball bearing cages 58 disposed between said rotors and a transversely extending supporting member 59 disposed and fitting within sleeve 48 and secured therein by the screws 60 havingheads countersunk in sleeves 48. Cages 58 also have oil grooves 58a therein at opposite sides thereof. It will thus be seenthat said rotors rotate in ball bearings at their'end portions. Supporting member 59 also carries ball bearings 6| in which the inner'ends of'shafts 3i! and 32 are journaled, the

adjacent ends'of said shafts being reduced in diameter; The rotors 5t] and 53 which as stated,

cam; member 'H' is secured within the path of vanes 64 and pivotstuds 63, said cam member being secured tomember 68 by screws 12 having their'heads countersunk in saidcarn, said cam is .thus held in stationary position. As shown in Fig. 5. each vane .64 has a hub journaled on pivot 63 ,and has a portion extending from said hub with ,a curved lower side bearing on the. periphery of. cam .member ll. Cam member H has. a plurality of portions Ha extending eccentrically to shafts 3i] and 32 and said camhas ports or openings 'l lb between said portions respectively.

As" shown in Fig. 5, said curved portions of vanes 64 ride upon the peripheryof cam 1|. It will also be seen that vanes 64 have their upper sur faces provided with curved portions 64a having thesame as the curvature of the hub portions of said vanes. Rotors 59' and 53. also have passages a and 53a extending therethrough just at the 'outer side of their hub portions; Rotors 50" and are also provided with ratchet or clutch teeth 5ilb and 531) at their inner sides.

The rotors 5| and'52 are as stated, also similar and have hub portions carrying the ball bearing assemblies 13 so that said rotors revolve on said bearings about-shafts 30 and 32. The rotors 5| and 52 have flange-like portions in which are threaded the pivotstuds 14 on which are oscillatably mounted the vanes 15. Vanes 15 are similar to vanes 64 on rotors 50and 53 except that they extendin the direction opposite to' those on rotors 55 and 53. It willbe seen that adjacent the rotors the studs 14 have collars thereon I seated in recesses in vanes 15 and rings 16 are secured tolthe ends of studs" I4 "by screws 11. Rings 16 are seated inrecesses in supporting member 68,. Acam I9 is disposed within the pathof vanes 15 being secured to member 68 by the screws having their heads countersunktheresaid cams thus being held in stationary position. Cams 19 are similar to cams H having the plurality of eccentric portions 19a and the openings'lQb thereb'etween; the cams 19 however;

beingarranged reversely to cams H. 'Rotors 5l and 52' have ratchet'or clutch teeth 5m and 52a at their remote sides.

"ember? aj 2 "surrounds shaft fttlbe'twfe'e'n 5 i sa 'bi si n d:tQa sli' able'fl ngi'tu'dinally to "shaft 30 the "splines iigtting tl'ifespaced keys 83 on shaft 30. Member '82, ifs bored "at one side to receive -tn en'dfoi a pin'85awhich is'carried onfa shaft B6 odr sled in m mber {68. Shaft "86 extends through sleeve 48 and through a slot "He in sleeve 4'Tandhassecuredthereto outside of sleeve aseg'innt or mutilatedgear as. A rack 9| having teeth at itscen tral portion with which thete'eth on gear 88 mesh, isdisposed at oneside of gear 8B'and secured to the outer sideo'fsleeve 41 byfthe straws-e9 having-their heads countersunkither'ein, It will be seen that-rotation of gearffitandshaft 86 will c'ause movement of mendliterv a2 longitudinally o f shaft 3a. Member 82 hasclutch -teeth fat each side thereof adapted to lienagedwith the clutchgteeth 50b and 51a on the rotors 150 'and "5|. In {Fig.4 member '82 is shojvfnasoonnected to rotor -50, A"me'm ber 92 similarin 'allrespects 'to membe'r 82, is splined to shaft tr n secured b the key's es thereon. Memberfl isnio'vedby a pin 96a carried by a shait "98 j'ournaled in'thejother "supporting me'mb :68, saidshaft extending through sleeve 48 itrirough a slot 41; "in sleeve '41 and having e uredtoit's outer end and 'at 'the outer side/of efl a mutilatedge'ar 99. Gear "99 is similar to (gear 8 8 and "adapted to mesh with the teeth oh'frack l'fll isecllredto the outersi'de of sleeve-41 'y the s ews Hill, said screws having countereiinkhads; I "As "shown inl igs.Zand 3 a stud85is journaled in one end of member 21 and has a reduced-portijonektending through bar ll midway of the latter. Said reduced portion is threaded and hasfa j'nut'thereon at the outer side of bar l1. Stud 85 has secured'thereto within member. 21 arm '81. Arm 81 extends longitudinally of and between members 21 and 41 and has a fork at its end embracing a'pin '84'secured t sleeve 41. "In conjunction with passages '210 and 21d a plateflfi'is r secured to sleeve 41 and when passages4'fdand48c are in register sleeve I closes sage'ild as sho'wn in Fig. Another plate I115 alsa carried by sleevejfl and when pas- 'lcand j 48b are inregister, said plate H16 121 ses passage'flc.

fIn' bp'eration, theiriotor 1'2 of the automotive 'vfehiclewill be operated "a usualand pump I3 willbe'operated to circulate a liquid'such as oil indtlie system including member IG, conduits l4 aiidl5'andsaid ump. With the parts in the position shown in Figs. 1, 4 and 5 the fluid from cohduit I l 4 wi11'enter member and pass through passage -21d into the chamber 216 between member 21 and sleeve 41. The liquid then passes through openings 41cand-48b which are in re;- ist'er. "Referring to Fig. 5, the liquid then en- 'gagesfthe upper sides of the vanes 64. The openings fleandlflb are directed against the vanes ia'lndare in effect nozzle inletsto the rotors. The

"liquid facts "ondthe vanesfitcausing rotation of,

otors50 and 53 and as this rotation occurs the i' ranesjrid'ejdown theinwardly extending surfaces of portionsl'l don-cam 1 l When the vanes reach "the epe ings Ilbthe liquid is released and disic'ha'grge'd "through said openings and will pass "through opnings 50a and 53a andthenthrough :Qpenings 28dfand '29?) into Chambers 2811 and f29a aind the liquid from chamber 29a'wil1 pass *thrpugh sassagem into passage 28b-and the liqui'dii'om ehamber 28d willalso pass out through passage 28b "and into conduit iiand back'to V 6 umpira. Itjwill benot'ed that a'sthe vanes ride down the surfaces of cam portions 11 a a greater "surfaceiscontinuously "exposed to the liquidso thatthere isvincreasingpressure and force of rotation on therotor. It may be stated that'the rings 66 and 68 act as sealing means for the 1iquid and also as reinforcing supports for'studs 63. The rotorsifl and are -thus drivenand since they'are-connected'by the membersBZ and '92 to 'the shafts 30 and -32 respectively, these shafts-are driven and power is tran'smittedto the rear wheels 33 and 340i the vehicle. The vehicle is thus drivenin a forward direction. "It will be understood that by manipulation of-pedals 2D and 2| the operator can bring the passages Mcand 43bas well as passages 4Tb and'2'8e, 290 more or less into register and the speed of rotation of the rotors and thus the power delivered to the Wheels ofthevehiclalnay be determined at the will of the operator. It will be understood that when openings "41c and 48b are partly in register some of the fluid from chamber 216 bypasses through openings 4"") and 2-8e and 250. Any speed from zero to maximum speed 'canbe easily and quickly produced.

Whenit is desired to have rearward motion on the vehicle the operator will manipulate pedals 20'and 2| to move bar I1 and thusmove pin 84 "andsleevedl. The liquid then 'passes throug'h passages Hit-arid 1 into engagementwitnthe bladesor vanes- 15. -These are 'acted upon-"by the 'liquid-as-previfously described inconnection with vanes 64. *l'tfotors tl and 52 an: "thus rotated. When sleeve-41 was rotated as stated, racks 9 l and fill -were*moved with -the-sleev e and theseengaged with or meshed-with thege'ars '88 -and 9'9,-thus rotating the same Withthe 'shafts' flfi and "96 thus moving members 82 and so that said members moved into engagement and became clutched tothe rdtorsil2.116. 52. 'Rotors'tu find-SS-Wfe at the same time disconnected so that *shafts--30 and 32 will be driven in the reversedir'ectionand the'vehicle will be moved'rearwardly. Thespeed of the rearward-movement can beregulated-and determined by the operator by manipulation of "p'edalsZD-and "2|. Thedevice can be'placgedin neutral position'by having bar H midwayof-the 'two'po'sitions indicated in FiggZ. Hit that time neither of the twoseries of openings -4'lc and48b or (Z and 480 will be "in register. However, j'openingsflb'will be brought intoregister respectively "with 'openings 28e "and"2 9c. The liquid 'circulatedwill then pass through the later openings "orpassages into'the chambers 28a'and 29a "ter of the openings 41;: and 482) or 41d and"48c.-

There will always be therefore, sufiicient power for'the vehicle. It will also be seen that whether "the two rotors "510 and '53 'are operating together or the two rotors 5| and 52 are operating'together,

and It so there will be very'littleffriction betweenthevanes and-said vcams. 'Ifhe partsare designed for easy manufacture and easerof' ase sembly. It will be apparent that-the device will have a high degree of utility for, the purp'ose'intended; f 1

lt will, of course, be understood that various changes maybe made in the form, details, arrangement and proportions of the parts, with- V out departingfrom the scope of applicants invention, whichv generallystated, consists in a device capable of carrying out the objects above set forth, in the parts and combinations of parts disclosed and defined in the ppended claims. What is claimed is: a

- 1.'A transmission unit having incombination,

points to drive the other rotor of each pair in the opposite direction and means in 'said'casing for connecting one of said rotors of each pair to a one of said shafts and for connecting the other rotor of each pair to the other of said shafts. l V 2. A transmission unit having in combination, a casing, an inner casing within and spaced from a said casing, means for delivering fluid under pressure between said casings, a pair of rotors within said inner casinghaving means thereon adapted to be engaged by said fluid for driving said rotors, a sleeve rotatable on said inner casing, said sleeve and inner ,casing having a series of openings therethroug h adapted to be brought into register for admitting fluid under pressure to one of said rotors to drive the same in one direction said inner casing and sleeve having a secondseries of openings therethrough adapted to be brought into register for admitting fluid under pressure to the other of said rotors for driving it in a direction opposite to said first mentioned rotor;

3.;A -transmission unit having in combination,

a casing; an inner casing spaced from said casing forming a chamber, meansffor delivering fluidunder pressure to 'said chamber, afsl'eeve mounted on said inner casing for rotation thereon; apair of rotors in saidlinner casing each having a series of vanes oscillatably mounted thereon, cams on which said vanes move in the rotation of said rotors, openings in said innerlcas ing and sleeve adapted to be brought into register 'mounted on said inner casing forming an annular chamber between thesame'and-said casing, said inner casing having. a series of inlet ports thereinand said sleeve also having a series of ports adapted to connect said inlet ports with said annular chamber upon rotation of said '8 sleeve, a rotor mounted within said inner casing comprising a plurality of vanes .oscillatable about. axes parallel to thelaxis of said rotorand adapted to be rotated by a liquid under pressure delivered through said ports,=a cam member with! in andeng'aged by said vanes, means for sup.- Vplyin'gl liquid under pressureito said annular chamber and means for rotating said sleeve to register said'ports to admit, fluid :to said rotor.

5. An hydraulic variable speed transmission comprising a casing, an innerlcasing fixedly mounted within said casing, a pair of rotors mountedrwithin saidinner casing and ,having 7 means thereon arranged respectively to be rotated in reverse directions by liquid underpressure'a sleeve rotatably mounted'on said inner casing and formingan annular chamber betweenthe same and said casing, means for deliveringifluid under pressure to said chamber; said inner'casing having two serie of inlet ports therein, one of said series being arranged toladmit liquid to one of said rotors to rotate it in'aforward direction and the other of said series being arranged to admit liquid under pressure'tosaid second rotor to rotate it in a reverse direction and said sleeve having two series of ports'therein adapted to connect said series of inlet ports respectively 7 let ports to thus admit liquid selectively toisaid 6. An automotive vehicle structure having in combination, a variable speedtransmission unit comprising a casing, a pair of. fluid driven rotors in said casing, a. shaft jour'naled at its ends in said casing about'whioh'said rotors rotate means for supplying fluid under pressure to said rotors to rotate them in opposite directionsrespectively and'means within said, casing fordirectly con-' necting said rotors alternately to said shaft. a

7 comprising circumferentially spaced oscillatable vanes, means for supplying fluid under pressure to said casing to engage said vanes and rotate rotors of eachof said pairs in opposite directions, a pair of coaxially arranged shafts disposed'sube stantially wholly within said casing atthecenters of and coaxial with said rotors; and means for selectively and directly'connecting one rotor of each pair to said shafts respectively so that said shafts may each be driven in oppositevdirections one pair of said rotors being idle while the other pair is being driven.

8; A fluid transmission device having in combination, a casing, a pair of rotors-insaid casing having means thereon adapted to beeng'aged by fluid for driving said rotors, a second pair. of rotors in said casing having means'thereon' adapt ed to be engaged by fluid for driving said rotors coaxial with said first mentioned rotors and arranged to'rotate in a direction opposite that of saidlfirst mentioned rotors, a pair of shafts journaled at their ends in-said casing and disposed rection or may both be driven in the opposite direction and means for delivering fluid under pressure to said rotors.

9. The structure set forth in claim 8, a casing extending about said first mentioned casing and forming a liquid containing chamber from which said fluid is supplied to said rotors and means for by-passing the liquid through said chamber without operating said rotors. I

10. A fluid transmission device having in combination, a casing, a pair of rotors in said casing having means thereon adapted to be engaged by fluid for driving said rotors, means for admitting fluid under pressure to said casing to drive one of said rotors in one direction without driving the other rotor or for driving said other rotor in the opposite direction and not driving said first mentioned rotor, a shaft journaled at its ends in said casing at the center of and coaxial with said rotors and on which said rotors revolve and means for connecting either of said rotors to said shaft.

11. A fluid transmission device having in combination, a casing, a pair of rotors in said casing adapted to be rotated by liquid under pressure, a

second casing surrounding said casing and forming a chamber thereabout for containing liquid under pressure, means for admitting liquid from said chamber into said first mentioned casing for rotating said rotors in one direction, a second pair of rotors in said first mentioned casing, means for admitting liquid from said chamber to said first mentioned. casing for rotating saidsecond pair of rotors in the opposite direction, a pair of shafts in said casing coaxial with said rotors, one of the rotors of each of said pairs rotating about one of said shafts and the other rotor of each pair rotating about the other shaft and means for connecting one of the rotors in each of said pairs to its respective shaft.-

12. A fluid transmission device having in combination, a casing, a second casing extending about said casing and forming a chamber for containing liquid under pressure, means for delivering fluid under pressure to said chamber, a rotor in said first mentionedcasing having means thereon adapted to be rotated in one direction by fluid to drive said rotor in said direction, a second rotor in said first mentioned casing having means thereon arranged to be rotated in an opposite direction by fluid to drive said second rotor in said opposite direction, a shaft in said casing coaxial with said rotors and about which said rotors revolve, means for selectively and controllably admitting liquid under pressure from said chamber to said first mentioned casing to rotate either of said rotors, the other rotor being idle and means within said first mentioned casing for connecting either of said rotors to said shaft.

13. A fluid transmission device having in combination, a casing, two pairs of rotors in said casone of said rotors being arranged so that said rotor is driven in one direction with the other 7 each comprising a, plurality of circumferentially ing, one pair of said rotors having means thereon constructed and arranged to be rotated by fluid in one direction and the other pair having means thereon constructed and arranged to be rotated by fluid in the opposite direction, a pair of shafts journaled at, their end portions in said casing coaxial with said rotors, one of the rotors of each pair being rotatable on one of said shafts and the other rotors of eachgpair being rotatable on the other shaft, means withinsaid casing for connecting one of the rotors of each pair to said shafts respectively and means for supplying liquid under pressure to said rotors to rotate either pair of said rotors, the other pair being idle.

14. A fluid transmission device havingin combination, a casing, a pair of fluid-driven rotors in said casing each rotor comprising a plurality of circumferentially spaces oscillatable vanes, said casing having a plurality of circumferentially spaced ports spaced thereabout for directing liquid to said rotors, a shaft supported adjacent its ends in said casing about which said rotors rotate, means for supplying fluid under pressure to said rotors through said ports to rotate either of said rotors, the other rotor being idle, said means operating to supply said fluid to rotate said rotors in opposite directions respectively and means for connecting either of said rotors to said shaft.

15. A fluid transmission device havingv in combination, a casing, a pair of fluid-driven rotors in said casing, means for delivering fluid under pressure to said rotors said casing having a plurality of circumferentially spaced ports thereabout for admitting fluid to said rotors, a sleeve fitting about and oscillatable about said casing, said sleeve having a plurality of circumferentially spaced ports therethrough adapted to be brought into and out of register with said ports .in said casing, certain of said ports and rotor idle and certain of said ports and. the other rotor being constructed and arranged so that said other rotor'is driven in the opposite direction with said one rotor idle, a shaft in said casing about which said rotors rotate, and means for connecting either of said rotors to said shaft.

16. A transmission unit having in combination, a casing, a pair of coaxial rotors therein spaced longitudinally along'their common axis,

spaced oscillating vanes, means for selectively supplying fluid to said casing and rotors alternately at circumferentially spaced points about said casing to drive said rotors in opposite directions, a shaft journalled adjacent its ends in said casing on which said rotors revolve and means for connecting either of said rotors to said shaft.

JOSEPH O. HAMREN. 

